Add feature test macro to enable pthread_mutexattr_settype()

Signed-off-by: Joseph Schuchart <[email protected]>

Author: devreal

opal/mca/threads/pthreads/threads_pthreads_mutex.h

@@ -40,6 +40,11 @@
  * available.
  */
 
+// needed for pthread_mutexattr_settype
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#endif
+
 #include "opal_config.h"
 
 #include <errno.h>